Baicalein, a component of an herb used in traditional Chinese medicine, appears to suppress several types of cancer by boosting the activity of a key transcription factor, according to City of Hope researchers and colleagues in China.
 John Yim (Photo by Thomas Brown) |
The findings hint at a strategy that could potentially make anticancer therapies more powerful, the scientists said. They reported their results Aug. 4 online in the journal Molecular Cancer Therapeutics.
Baicalein is a compound derived from a member of the mint family called the Baikal skullcap, or Scutellaria baicalensis. Called huang qin in Chinese, the root of this plant is one of the most popular extracts used in traditional Chinese medicine.
According to senior author John H. Yim, M.D., associate professor of surgery at City of Hope, the researchers happened upon baicalein when they screened a variety of natural extracts to look for compounds that could boost the cancer-fighting activity of a transcription factor called interferon regulatory factor-1, known as IRF-1.
“We know that IRF-1 suppresses tumors,” Yim said. “The mechanisms are complex, but research has shown that IRF-1 can keep cancer cells from proliferating as well as encouraging cancer cells to kill themselves through apoptosis. It also makes cancer cells more vulnerable to the immune system.”
Because IRF-1 can act against cancer in different ways, the scientists believe that encouraging IRF-1’s activity could be an attractive therapeutic strategy — and perhaps even a tactic for preventing the disease.
Of all the natural products they tested, baicalein was the most powerful enhancer of IRF-1 activity. When they tested it in stomach cancer and breast cancer cells in the lab, they found it inhibited the cells’ growth. Baicalein also inhibited breast tumors in mice, with no toxicity.
“Our hope is that this compound could enhance IRF-1 activity and contribute to cancer therapy without toxic side effects,” Yim said.
The scientific team is the first to connect baicalein to IRF-1 activity, but baicalein has spurred a flurry of cancer research worldwide over the last several years. Within the last year alone, scientists have reported on its effects on pancreatic, colon and lung cancer cells through several mechanisms. It also has shown activity against multiple myeloma and prostate and liver cancers in the lab.
The lead author of the study was Jinbo Gao, M.D., Ph.D., who performed this work as a postdoctoral fellow at City of Hope and is now an academic surgeon at Huazhong University of Science and Technology in China. City of Hope co-authors included Yujun Wang, Ph.D., Quanhua Xing, Ph.D., Yasir Akmal, M.D., Jin Yan, B.M.D., and Julia Kang, a summer student, in the Department of Surgery; Claudia M. Kowolik, Ph.D., and David M. Lu of the Department of Molecular Medicine; and M.L. Richard Yip, Ph.D., director of the High-Throughput Screening Core.
Previous work on IRF-1 and cancer suppression has been published by the Yim lab in Cell Death and Differentiation, Cancer Research and Oncogene. The latest research was supported through the National Cancer Institute, Susan G. Komen for the Cure and the China Scholarship Council.
Editor’s note: Other City of Hope scientists are studying another huang qin component called baicalin to see how it boosts growth of blood vessels. To learn more, visit www.cityofhope.org/hopenews.
